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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Administrative data

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
07 May – 19 Jun. 2008
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study
Cross-reference
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report Date:
2008

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Principles of method if other than guideline:
Closed test system: water-accommodated fractions (WAF) and the biological test were conducted under closed conditions
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): naphthalene oil
- Molecular formula (if other than submission substance): not applicable
- Molecular weight (if other than submission substance): not applicable
- Substance type: organic
- Physical state: solid
- Stability under test conditions: WAF (water accommodated fraction) limited
- Storage condition of test material: room temperature, exclusion of light

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Samples for TOC-analysis were taken at 0 h and 48 h

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Water Accommodated Fractions (WAFs) prepared by stirring various amounts of the test item in Daphnia-medium
for 24 h with magnetic stirrers. The WAFs were prepared in closed glass vessels.
The test loading rates of Naphthalene Oil were weighed in weighing scoops that were afterwards placed into the vessels.
The beakers were then filled with Daphnia-medium.
Mixing was carried out at a speed that was slow enough not to cause dispersion or emulsification of the undissolved fraction
of the test item. To ensure this, the vortex developed at the surface by stirring was set at ~ 10 % of the water depth.
After stirring for 24 h the WAFs were allowed to stand for 1 h before use to facilitate phase separation.
The test vessels were closed directly after the transfer.
The extracts gained with this method were clear.

- Differential loading: control, 1 mg/L, 2.5 mg/L, 5 mg/L, 10 mg/L, 25 mg/L , and 50 mg/L
- Controls: without test material (blank; Daphnia medium)
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): none
- Evidence of undissolved material (e.g. precipitate, surface film, etc): no

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia
- Strain: --
- Source: origin German Environmental Ministry
- Age at study initiation (mean and range, SD): =< 24 h
- Method of breeding: The animals are cultivated in a climate-controlled room (light/dark = 14 h/10 h; illumination: Gro-Lux fluorescent tubes).

- Feeding during test
- Food type: The animals are fed with algae (Desmodesmus subspicatus)

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Post exposure observation period:
none

Test conditions

Hardness:
see data under "salinity"
Test temperature:
19.8 – 21.2 °C (20 °C ± 2 °C)
pH:
8.0 - 8.1 at 0, 24 and 48 h
Dissolved oxygen:
6.3 - 7.4 mg/L at 0, 24 and 48 h
Salinity:
The total of Ca- and Mg-ions was 2.5 mmol/L, the ratio of Ca/Mg was 4:1, the ratio of Na/K was 10:1. The total alkalinity of the solution was 0.8 mmol/L, the pH-value was 7.8 ± 0.2.
Nominal and measured concentrations:
Time [h] Control 2.5 mg/L 10 mg/L 50 mg/L (loading)
=================================================
0 1.9 4.3 7.6 17.1 mg/L (TOC of WAF)
48 1.6 3.9 7.9 17.1 mg/L (TOC of WAF)
====================================================
Oil-related TOC values were about 2.0 - 2.5 mg/L (at 2.5 mg oil/L), about 5.5 - 6.5 mg/L (at 10 mg oil/L) and 15 - 16 mg/L (at 50 mg oil/L).



Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: glass beaker, 100 mL, test volume: no data
- Aeration: none
- Renewal rate of test solution (frequency/flow rate): none
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates): not applicable


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
- Total organic carbon: no data
- Alkalinity: 0.8 mmol/L
- Ca/Mg ratio: 4:1
- Conductivity: no data
- Culture medium different from test medium: no


OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light, 8 h dark
- Light intensity: no data, Gro-Lux fluorescent tubes


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2 - 2.5
- Range finding study: not performed under closed conditions

Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
48 h
Dose descriptor:
EC10
Effect conc.:
ca. 1 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks:
1/20 (5 %) immobile
Duration:
48 h
Dose descriptor:
EL50
Remarks:
effective loading
Effect conc.:
1.7 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EC100
Effect conc.:
ca. 3.5 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
NOELR
Remarks:
No-observable effect loading rate
Effect conc.:
<= 1 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks:
1/20 (5 %) immobile
Duration:
48 h
Dose descriptor:
LOELR
Effect conc.:
2.5 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks:
18/20 (90 %) immobile
Details on results:
- Other biological observations: number of moults incipient reduction from 1 mg/L
- Mortality/immobilisation in control: 0/20
- Other adverse effects control: none
- Abnormal responses: none, except steep dose-response curve
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: none
- Effect concentrations exceeding solubility of substance in test medium: none
Reported statistics and error estimates:
Determination of the EL50 (EL= Effective Loading) and NOELR was accomplished using Probit-analysis (Finney-method, lognormal distribution; confidence limit 95 %, significance level: p <0.05).

Any other information on results incl. tables

Table 1: Immobilisation rate in dependence of time and loading rate, number of carapace moults, and

number of living animals trapped at the surface [number per total animals, %] (Report Tab. 3)

Control

1mg/L

2.5 mg/L

5 mg/L

10 mg/L

25 mg/L

50 mg/L

Number

[%]

Number

[%]

Number

[%]

Number

[%]

Number

[%]

Number

[%]

Number

[%]

Immobilisation 24 h

0/20

0

0/20

0

8/20

40

20/20

100

20/20

100

20/20

100

20/20

100

Immobilisation 48 h

0/20

0

1/20

5

18/20

90

20/20

100

20/20

100

20/20

100

20/20

100

Moults 48 h

18/20

90

17/20

85

12/20

60

0/20

0

0/20

0

0/20

0

0/20

0

Living animals at
the surface 48 h

0/20

0

0/20

0

0/20

0

0/20

0

0/20

0

0/20

0

0/20

0

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
- Immobilisation in the control: 0 % (nominal value ≤10 %) - Dissolved oxygen in all vessels: >= 6.3 mg/L (nominal value >= 3 mg/L)